This invention relates to a transporter having permanent magnets for use in combination with an iron or steel sheet ceiling or similar structure having a horizontal, downwardly facing supporting surface, the transporter also having a plurality of rollers contacting the ceiling or supporting surface and permitting free movement of the transporter in any direction across the ceiling or supporting surface, and means depending from a frame member of the transporter for attachment to and support of a load.
The use of electromagnets for lifting and transporting magnetic material such as coiled steel strip is well known in the prior art. In such structures an electromagnet is generally suspended at the end of lifting means, such as a block and tackle, from a frame structure on tracks in a single direction. U.S. Pat. Nos. 2,220,561; 2,651,538 and 2,946,616 are representative of structures of this type.
U.S. Pat. No. 2,220,561, issued November 1940 to Ward, discloses an electromagnet for lifting coiled steel strip. The electromagnet is mounted on a yoke or body, and the magnet produces a ring-shaped flux distribution with lines of force extending generally around a central axis above and radially thereof so that greater efficiency is obtained in lifting annular shapes. A chain and hook are suspended beneath the electromagnet for carrying a selected load.
U.S. Pat. No. 2,651,538, issued September, 1953 to Stahmer, shows an electromagnet used to pick up heavy materials. A plurality of magnetic units is mounted in an outer casing. Hooks are provided to engage a desired load. Housings pivot about pins.
U.S. Pat. No. 2,946,616, issued July, 1960 to Carter et al, discloses an electromagnetic lifting device especially adapted for lifting coils of steel strip. An electromagnet is mounted in a housing. Rollers are mounted on a post and engage the upper face of a lower wall. A spreading member is carried by a plunger and a plurality of fingers. The fingers can be shifted from a nested position to positions separated from each other and away from the lower end portion of the plunger. Movement of the fingers is effected by the rollers.
U.S. Pat. No. 2,426,795, issued September, 1947 to Sjostrom, discloses a magnetic floor sweeper adapated to pick up magnetizable scraps or small pieces such as nuts, screws, bolts and metal shavings which may be on floors or work benches. A permanent magnet is mounted on a base frame. A centrally located opening or recess is provided between a non-magnetic plate and the floor. The sweeper is mounted on a plurality of casters and may be pushed in any desired direction.
While it is evident that the prior art has disclosed the use of magnets in a lifting device for picking up magnetizable material, to the best of applicant's knowledge there is no suggestion of the use of bipolar permanent magnets for the purpose of holding a transporter to a magnetizable metal ceiling and at the same time permitting movement of the transporter in any desired direction across the ceiling.
It will be recognized that free movement of a transporter in any desired direction, e.g. in a building, loading dock, or truck body, is highly advantageous and facilitates the handling and transporting of loads. Such a transporter will automatically center itself over a load to be lifted as soon as the means for attachment to the load is placed under tension. The use of permanent magnets obviates the need for connection to a source of electric current which is of course required for electromagnets.